Apparatus for making endless v-belts



Nov. 7, 1950 H. G. LYKKEN 2,529,301

APPARATUS FOR MAKING ENDLESS V-BELTS Filed Oct. 14, 1946 4 sheets-Sheet 1 lNVENTOR HENRY G. LYKKEN BWAMIIMWW A TTORNE vs Nov. 7, 1950 H. G. LYKKEN 2,529,301

APPARATUS FOR MAKING ENDLESS v-esurs Filed Oct. 14, 946 ,4 sums-sheet 3 "6 ATTORNEYS Nov. 7, 1950 H. s. LYKKEN 5 3 APPARATUS FOR MAKING ENDLESS Vr-BELTS;

Filed 00". 14, 194 AT SIiQj'etS -Sheet 4 3 HR "s -R Haj/3 /NVENTOR HENRY G. LYKKEN ATTORNEYS Patented Nov. 7, 1950 UNITED STATES PATENT OFFICE APPARATUS FOR MAKING ENDLESS V-BELTS 12 Claims.

This invention relates to an apparatus and method for producing endless belts that are composed of heat curable material. The most common application to which the invention is applied and which is described herein as illustrative of the invention is the manufacture of endless V-belts composed of heat vulcanizable rubber, cord and fabric construction. Heretofore, the manufacture of V-belts has been carried out by preliminarily forming a belt from its constituent parts of cord, fabric and rubber composition, after which the uncured belts are molded in one or the other of two ways. For the shorter sizes of belts the uncured belts are placed upon multiple ring or drum molds and the molds with a number of belts upon them are placed in a, retort and cured under heat and pressure. For the larger sizes, the belts are cured a part Of the circumference at a time in successive steps. In this method a portion of the uncured belt is placed in a straight or curved mold of appropriate cross section and heat and pressure is applied to vulcanize that section. The mold is then opened and the belt is then moved so as to bring another uncured portion of the belt in the mold. The mold is then reclosed and the second portion vulcanized. The process is repeated until the entire periphery of the belt is vulcanized.

While this method is comparatively satisfactory and many belts have been made that way, it

has a disadvantage that the belts must be removed, reclamped and cured at several positions around the circumference of the belt in order to complete the molding operation. This not only consumes a great deal of labor and time,

as well as machine time, but also produces areas of overlapping vulcanization, for the portions of the circumference vulcanized must be overlapped in order to be certain that no section of the belt is uncured. Accordingly, there are some portions of the circumference which are cured more than others and hence the belt does not have quite the same flexibility all around.

A further disadvantage of each of the foregoing conventional methods has particular reference to the use of a plurality of belts in multiple or, as it is known, in multiple V-belt drives. When multiple V-belts are used, it is necessary to match the belts exactly for length for if one of the belts is tighter than the remaining belts, it will assume a disproportionately large share of the load with detrimental results. Heretofore, it has been necessary to match the belts for length after they have been completely manufactured in order to obtain sets of even reason-v ably corresponding length. This has been especially difiicult because in both of the conventional methods the belts are molded without any stress being placed upon the load-carrying cords of the belt. Hence, belts made in accordance with prior methods have a high percentage of residual stretch which is non-uniform from belt to belt. Hence, use of such conventional belts in multiple has been subject to the disadvantage of non-uniform loading.

Another disadvantage of prior methods of V-belt manufacture involves the fact that each belt had to be preliminarily formed to the approximate configuration of the V cross section prior to molding. This has necessitated an individual handling of the belts during manufacturing.

It is an object of the invention to provide an improved method and apparatus for manufacturing endless belts of heat curable material and more particularly to provide improved methods and apparatus for manufacturing V-belts. It is also an object of the invention to provide improved methods and apparatus capable of yielding highl finished, dimensionally accurate belts quickly and at low cost as compared to prior methods and to permit manufacture of the V-belt assemblies prior to curing by multiple methods. It is also an object of the invention to provide improved methods and apparatus for simultaneously molding a plurality of belts under identical conditions so as to provide belts of identical cross section and length.

Other and further objects of the invention are those inherent in the apparatus herein illustrated, described and claimed.

The method of the invention is illustrated with reference to the apparatus of the invention, the latter being shown in the drawings in which Figure 1 is a top elevational view of one form of machine for carrying out the method of the invention.

Figure 2 is a longitudinal sectional view taken in the direction of arrows 2-2 of Figure 1.

Figure 3 is a schematic fragmentary sectional view of a portion of the apparatus of Figure 1, partly in section, taken in the direction of arrows 33 of Figure 1.

Figures 4, 5, 6 and 7 are sectional views of the belt in place on the carrying pulleys of the apparatus of the invention showing succesive stages of forming and curing the belt.

Figures 8 and 9 are side elevational views of a modified form of the invention used for simultaneous manufacture of a plurality of long or uncured belt had a cross section of rectangular shape, or changes any irregularities ina preliminarily V-shaped uncured belt to conform to the exact shape of the grooves 22. The progressive movement of the belt downward is illustrated in Figures 5, 6 and 7. In Figure 6 the belt has been pushed partly down and has begun to take the V-belt shape, whereas in Figure 7 the belt is pushed completely down and has the complete V-belt cross section defined by the walls It, H and I8 and by the under side of the flexible band 30.

While the belt is thus being run down deeper and, deeper into the groove and shaped, it is heated by any suitable means. Thus, the pulleys and 26, or at least one of them, may be heated by any convenient heating arrangement, such as an electrical heater, steam, gas flame or the like, and, if desired, the belt may be additionally heated between the pulleys by a high frequency electrical dielectric heater or diathermy apparatus hereinafter described in greater detail. In Figure 3 the pulleys 25 and 25 are illustrated as being heated electrically. Thus, each of the pulleys has a plurality of electric heater cartridges 38 embedded in the solid portion of the pulley. The cartridge heaters 38 are each wired to bus bars 39 and 49. An incoming service connection ii is connected to bus bar 49, whereas an incoming service connection 42 is connected through a thermostatic control switch 49 and thence through line to to the bus bar 39. The thermostatic switch G3 is mounted in the pulley and accordingly regulates the heat input in accordance with the temperature thereof.

The heating of the uncured belt softens it and makes easier the deformation required to change from the rectangular or roughly formed V of the uncured belt to the smooth and regular V of the finished belt. After the belt has been heated, softened and gradually run down into the pulley grooves and heated for a sufficient time, the heat curable material of the belt completely permeates the cords it and the cloth covering 5. The material in the cloth covering and in the deepest part of the groove is heated quickest and hence is the first to begin to cure and to become less plastic. At this time pulley 27 is moved downward as indicated by arrow 29, and the partially cured belt is tensioned with the result that cords in layer l9ll are brought to design tension. The cords have little tendency, however, to pull into the pad section l3 because of the advanced curing and hence greater toughness of this section. Arrangement is made so as to stop the relative movement of the shafts 34 and at a limiting position so as to limit the downward run of the thin flexible metallic bar 39 into the pulley groove space. In this way extrusion of the hot and somewhat plastic heat curable material around the band 39 in the slot is prevented. Similarly, only prescribed tension is placed on pulley 21, thus permitting the production of belts wherein the tension of the belt cords and its dimensions are accurately fixed and reproduceable.

Referring to Figures 1 and 2 there is illustrated a production machine for carrying out a simplified form of the method of the invention wherein the belts are run down to shape them and are tensioned in one operation. The machine consists of frame posts 50 and 5i connected by a bottom frame member 52. The tops of the posts 59 and 5| terminate at blocks 54 and 55 whichaie apertured to receive a pair of round bars56 and 58, extending horizontally between the frame posts. The upper frame block 55 is also provided with bearing seats 60 and BI in which a tubular shaft 62 is.journaled. The shaft is provided with a driving sprocket 63 which is connected by a chain belt 64 so as to run over a driving pinion 65 on the countershaft 66, the latter being driven by belt 61 from the motor 68. A variable speed drive of any conventional variety may be provided between the motor 68 and countershaft 66, if desired. Upon the parallel rods 56 and 58 there is mounted a cross head generally designated!!! which is provided with a pair of bearing blocks H and 12 for rotatably mounting the hollow shaft 74. Upon the cross head ll] there is also a central pillow block 15 which is apertured to receive the threaded end 16 of a piston rod 71. A pair of large nuts 18 and 19 upon the threaded end of the piston rod permits preliminary adjustment of the cross head 70 with reference to the piston rod for setting the apparatus to handle belts of different lengths.

8|. The cylinder is provided with inlets 82 and be applied, if desired, for moving the piston toward or'away from the fixed shaft 62. Upon slide rod 19 there is mounted a stop collar 84 having a removable pin 85 which can be fitted into any one of a plurality of apertures 86 provided at spaced intervals along the rod 56. The stop collar 84 limits the movement of the cross head 10 toward the piston end of the machine and thus limits the downward running of the thin flexible band into the grooves of the pulleys, as previously described.

The ends of the shafts 62 and 14 extend beyond the bearing blocks 60, 6|, H and 12, respectively, and upon the outer ends there are mounted pulleys 88, 89, and 9|. Each of the pulleys is illustrated as having four grooves, although many more grooves may be provided, if desired. The grooves in each instance have a bottom shape 22, Figure 4, of the belt cross sectional shape desired to be produced which maybe a V-belt, if desired, or any other cross sectional shape, and above the bottom portion 22 the walls of the grooves are spaced and are parallel to each other. Each of the pulleys 889I is provided with electric heater elements as previously described for pulleys 25 and 26, Figure 3. The heater of pulleys 88 and 89 are wired to slip rings 92 and 93 on shaft BI, and the heaters of pulleys 90 and 9| are wired to the slip rings 94 and 95 on shaft 14. The slip rings are fed by brushes 91, 98, 99 and I00 which are in turn connected to the feeders HH and H32 8| as shown in Figure 2 when the cross head 10- is against the stop collar 84, the stop collar having previously been adjusted so as to provide the belt size desired to be produced. The nuts 78 and 19 are then turned down tightly and air or other fluid under pressure is introduced through pipe 82 and the piston 89 is accordingly driven to the left, as shown in Figures 1 and 2. The uncured belts B are then laid in place on the pulleys 89-9l and 89+90, and over each belt there is placed a w thin flexible metallic band 30. The air supply to line 82 is then interrupted and air is gradually introduced through pipe 83. This causes the pis- The piston rod 11 carries a piston 80 which moves back and forth in cylinder 7 tonzfifl tube gradually moved to the right. At the same time themotorjfi8 is started. As the :piston 80. moves to .the right it-drags cross-head 1.0 like.- wise, and this, causes the flexible metallic bands 30 gradually to run down into the grooves of the pulleys and force the uncured belts deeper and deeperinto the pulley grooves to shape them. As the beltis run down, heat is supplied by the heater elements of each pulley and this softens the rubber composition enabling itreadily to conformto the shape of-the pulley groove. The movement is soonarrested by the stop 84 which is positioned so as toholdthe cross .head when the thin flexible metallic bands 30 have pushed the belt material completely to thebottom of the grooves in which, in each case, the belt runs. The running is continued as heat is applied and after a suitable period the curing of the material is accomplished, after which the .fiuid supply to line 83 is interrupted and fluid is directed into line 82. causes the cross head It ,to move to the left where the belts are loosened and can be removed.

Since the lower or pad portion I3 of the V-belts is heated and worked more than the upper por tions III and I2, it is firstto cure and it thus establishes a relatively firm base against which the cords in section i'i.|II are tensioned when the cross-head III is moved to its limiting position. Accordingly, there is little tendency for the cords to pull downwardly into the pad. If desired, the pad I3 may be made of rubber composition having moreaccelerator and hence a shortor curing time than portions Ill-II and I2 so as to allow ample differential in the curing rates of the two sections. This permits. the pad portion I3 to become quite firmas tension is applied to the cords in section I.II!I at the limit of movement of the cross-head.

It will'be noted that in the foregoing operation a plurality of belts are cured simultaneously in i each operation. The number may be greatly increased by providing'a greater number of grooves in the pulleys. Furthermore the belts are cured to precisely the same dimensions, and the belts are accordingly dimensionally accurate both as to crosssection and length and may be used in multiple in multiple V-belt drives without danger of overloading or underloading any of the belts.

Referring to Figures 8-l3 there is illustrated a preferred form of the apparatus of the invention which, however, operates on the same principle as explained with reference to Figures 3 7. In, these figures the frame of the machine consists of posts Hi5 and IE6 which terminate in head boxes I68 and I39. In, this machine the head boxes serve to support four parallel slide rods III], l'II, H32 and H3, Figure 1 2. The head box I09 iscprovided with journals I-I Sand 'I It in which a hollow shaft I l rotates. 'Shaft I I! is provided with a driving sprocket I18 (Figure 11) and at each of its outwardly protruding ends thereis mounted a pulley I13 as described with reference to the apparatus shown in Figures 1-2, the pulley being provided with a plurality of belt-forming grooves. The shaft HT is likewise provided with slip rings I23 and l2I which serve to conduct electricity to the heating elements of the belt-forming pulleys, there is mounted a piston I22 having a piston rod l23 connected through the link I24 to a first cross head I25. The cross head I25 is as shown in cross section in Figure 13 and is provided with journals I26 and I2! which serve to support the shaft I28 upon t eouter ends of which additional grooved belt-forming pulleys I14 are mounted,

This

Upon the head box I08 the grooves of which are aligned with those of pulleys I73. The shaft I28 is not provided Witha driving sprocket but is provided with slip rings I29 and I30 through which electricity is conducted to the heating elements mounted in the pulleys.

The cross head I25 is connected through a link I32 to the piston rod I33 of cylinder I34, the latter cylinder being mounted in a second cross head I35. The cross head I35 serves not only as a mounting for the cylinder I34 but is likewise provided with a pair of outwardly protruding stub shafts I37 and I38, and upon these shafts there are mounted flat grooved idler pulleys of which one such pulley I39 is illustrated in Figures 8 and 9, it being understood that there is a similar pulley upon the corresponding stub shaft at the opposite side of the machine.

The position of the cross head I35 relative to the cross head I25 is determined by the position of the piston operating in cylinder I34. As the piston rod I33 is projected relative to the cylinder I35, this causes the cross head I35 to be moved to the left, carrying cylinder I34 with it, since the pistonI33 is anchored to the cross head I25 which is in turn anchored through the link I24 to the piston rod E23, Accordingly, the position of the two cross heads I25 and I35 is determined in the first instance by the position of the piston rod I23 operating in cylinder I22, and the position of cross head I35 relative to I25 is in addition determined by the position of piston rod I33 in cylinder I34,

Upon the rods iIilI i3 there is also mounted a third cross head I which likewise carries a cylinder I46 in which the piston rod I41 operates. The rod I 37 is connected by link I48 to the frame piece I49 on the head frame member I99. The position of cross head I45 is accordingly determined by the operation of piston rod I 41 connected to its piston in cylinder I46. The cross head I45 has the same cross sectional shape as for the cross head I35, namely that shown in Figure 12, and it is provided with stub shafts, one of which I4I is illustrated in Figures 8 and 9, it being understood that there is an axially aligned stub shaft at the opposite side of the frame. Stub shafts Ml and its opposite frame extension carry fiat grooved idler pulleys, one

i of which I42 is shown in Figures 8 and 9.

Opposite ends of cylinder I22 are connected through flexible fluid supply lines I and I5I to a two-way valve I52 which is supplied with fluid under pressure by line E53, as indicated by the arrow i5 3 The valve I52 is provided with a long operating handle i525 which extends above the machine, When it is moved towards the position R, the piston is moved to the left, thereby permitting the release. of the belts and the thin flexible band 3 from the ulleys. When the operating handle 555 is moved to the position S, the piston rod I23'is drawn to the right, thus applying the shaping action which drives the uncured belts into their pulleys during the shaping and curing operation. Similarly, fluid under pressure is applied as indicated by arrow I56 through the line I5? to the two-way valve 658 which is connected by means of lines I59 and I60 to opposite ends of the cylinder I34 and the valve I58 is likewise provided with a long operating handle I5I which extends above the machine. When the handle is moved to the position R, the piston and piston rod I33 move (relatively) toward the head of the cylinder I34, thus drawing the cylinder 53d to the right. This serves to shorten the distance between the centers of stub shafts I31I38 on cross head I35 and shaft I on cross head I25, thus likewise permitting release of the short belts when they are being cured as in Figure 8. As indicated by arrow I62, air is supplied through line I63 to the two-way valve troduced to the cylinder I46 so as to move the piston rod I41 (relatively) towards the head of the cylinder I46, thus drawing the cylinder and cross-head I45 towards the head frame I09. This permits release of the short belts when they are being shaped and cured as shown in Figure 8. Extending' lengthwise from the head frame I08 to I09 there is a longitudinal bar I68 which is apertured at intervals throughout its length to receive stop pins I16, I1I or I12 in order to predetermine the limit of movement of the various cross heads along the rods, it being noted that the bar I68 is in contact with the upper surface of not only the head frame members I08 and I09, but also the upper surface of each of the crossheads; Thus, by properly adjusting pins I10, HI and I12, the position to which the cross heads are moved by their pistons and cylinders can be predetermined beforehand. 1

In Figures 8and 9 the main belt forming pulleys 'are shown at I13 and I14, it being. understood that there are counterparts of these pulleys at the opposite ends of the shaft Ill and I28, upon which these pulleys I 13 and I14 are mounted. 1

The pulleys I13 and I14 and corresponding pulleys at the opposite ends of their shafts are arranged to be heated electrically as described with reference to Figure 3, thermostatic control being provided for the electrical heaters, if desired. Likewise, if desired, there may be provided spaced plates I15 and I16, I11 and I18 for Figure 8 or spaced plates I19 and I80 for Figure 9 to which high frequency, high voltage electrical energy may be applied for heating the belts by diathermy action, in addition to the heat supplied by the forming pulleys. The heat supplied by the forming pulleys is sufficient for smaller cross sectional belts, but additional heat supplied electrically by the diathermy plates I15-I80 serves to provide a rapid temperature rise for the deeper sections of the belt most remote from the heated pulley surfaces, and thus permits rapid curing without undue time on the machine.

The pulleys I39 and I42 of Figures 8 and 9 are idler pulleys, but it'will be understood that they are provided with belt-forming grooves, the same.

as those for the larger beltforming pulleys.

In operation the apparatus of Figures 843 may be used in either of several ways. When formin relatively short belts, the apparatus is used as shown in Figure 8. In this form the uncured belts in multiple are run over the pulleys I13 and I42 and other uncured belts are run over the pulleys I14 and I36. The pressure-applying thin flexible metallic band 30, however, runs over the pulleys I13 and I14. Thus, when pulley I13 is rotated through its driving sprocket H8, this serves to cause its rotation and the pressureapplying belt I30 which runs over the pulley I14 causes the rotation of the latter pulley which in turn rotates the pulley I 39. In curing short belts as shown in Figure 8, the valve handle I55 is first moved to the release position which serves to move piston rod I23 to the left, as shown in 10 Figure 10, thus moving cross head I25 to the left to permit release of the thin flexible metallic band from all of the pulley grooves. The operating handles I6I and I61 are likewise moved to the release'position. This, in each instance,

1 moves the piston rod I33 or I31 towards its piston head, and the eifectis to move the cross head I35 toward cross head I25 and the 'crosshead I towards head frame I09, thus bringing the pulley I39 to its closed position relative to the large pulley I14 and the pulley I42 to its'closed position relative to the large pulley I13. In'this position'the uncured belts which have been'prefabricated as previously explained, are placed in the pulley grooves and the thin flexible metallic bands 30 are then placed in the grooves on top of the uncured belts and the operating handle I is moved first to shaping position. When this occurs the piston rod I23 moves to the right as shown in Figure 10 and draws the cross head I25 to the right, thus gradually forcing the thin flexible bands 30 downwardly in the groove in which, in each instance, they are operating, thereby gradually to move the uncured belt and meanwhile heated belt down into the groove and form it to the V shape. When the shaping'of the belt is in progress, pulleys I39 and I42 run idle with little or no tension on the belts, which accordingly shape and begin to cure. Curing occurs first in the pad sections I3, as previously explained due to the greater shaping, thinner section and greater depth of contact with 'the pulley grooves. As curing is about to be completed in the pad sections, the operating handles I6I and I61 are moved'to their stretchingp'ositions S (Figure 10) and this causes cross head I 35 to be moved to the left, as shown in Figure 10, and causes a tension to be applied to the cord sections I0-II of the belts BI as they are cured. Similarly, piston rod I41 is moving outwardly from its cylinder I46, but since the piston rod is anchored through link I48 this causes the cross head I 45 to move to the right and gradually place a tension on the belts B2 in which the cords in sections I0II are similarly tensioned. Additional heat input to the belts may be provided by means of the high frequency electrical heaters I15I16 and I11I18 to help curing of large belts. The limiting position of the cross head I25 to the right is determined by the stop pin I12, and the limiting positions of the cross heads I 35 and I45 moving towards each other are determined by the stop pins I10I10. The positions of stop pins I10I10I12 are, of course, predetermined in accordance with the dimensions and design tensioning of the belts being produced. After the beltshave been forced into thebeltshaping space of the pulley grooves, then tensioned and heated for a sufficient time, the material of which the belts are composed is adequately cured, whereupon the handlesl55, I 6! and I 61 are all moved to the releasing position R, Figure 10, which slacks the tension throughout the machine andpermits thebelts andthe thin flexible bands 30 to be removed.

If desired, the apparatus ofv Figure 8 maybe utilized to cure belts by running them over pulceptionally long belts are: desired to be manufactured. on a given size machine and in any event where separate and successive forming and tensioning are desired, the belts are run over idler pulleys I39 and I'42 of Figure 9 which have. fiat bottom grooves therein. The shaping action is provided by the pulleys I13 and I'M primarily while the pulleys are held in such position as not appreciably to'tension the belt. Then when vulcanization (curing) has been partially completed, the pulleys I39 and M2 are moved apart so as to apply tension to the belts and thus apply a predetermined (design) tension to the cords therein. While this is done the belts are continuously being run on the pulleys and vulcanization is completed. The stops I1I are, of course, positioned so that when cross-heads I35 and I45 are moved apart by air pressure appropriately applied, the belt will have a predetermined (design) length and the cords therein will be tensioned to the precise amount for best service. It may benoted that when the belts are run as in Figure 9, the movement of valve operating handles I6I' and I61 is opposite from the direction of movement explained with reference to Figure 8, in order to place tension on the belts, or stated another way, the S and R positions of valves I58 and IE4 are reversed for Figure 9 operation.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments herein except as defined by the appended claims.

What I claim is:

1. An apparatus formaking endless belts of heat curable material comprising a pair of pulleys each having therein a belt groove which has parallel side walls throughout a first portion of the groove depth, said parallel side walls being of a depth at least as great as the thickness of the belt to be formed thereon and a different cross-sectional shape below said spaced side wall portion which is the same cross section as that ofthe belt desired to be produced, means mounting the pulleys for rotation about substantially parallel axes, and for varying the distance between said axes as the pulleys are rotated, an endless thin flexible band having a width such that it fits neatly into the parallel side wall portions of the pulleys for running as a backing belt therein with the belt being manufactured pressed into the groove space below the band, and means for rotating the pulleys and for simultaneously heating the belt being manufactured.

2. The apparatus of claim 1 further characterized in. that at least one of the pulleys is electrically heated.

3'. The apparatus of claim 1 further characterizedinthat the means mounting the pulleys for rotation about substantially parallel axes and for varying the distance between said axesincludes a cylinder and piston connected to the pulley mountings for moving themapart.

4. The apparatus of claim 1 further characterized in. that the means mounting the pulleys fo rotation about substantially parallel axes and for varying the distance between said axes includes a screw connection between said axes for preliminarily adjusting the distance between said axes and also includes a cylinder and piston for moving the axes further apart as'the pulleys are rotated during curin belts thereon.

5. An apparatus for making endless belts of heat curable material comprising a frame, a shaft rotatably mounted on the frame, a second shaft mounted on the frame and substantially parallel to the first shaft, means for moving at least one shaft relative to the other while rotating and while maintaining their substantially parallel relationship, pulleys mounted on the shafts, each pulley having at least one groove therein aligned with a functionally identical groove of the other pulley, said rooves each having parallel side walls throughout a portion of their depth, said parallel side walls having a depth at least as great as the thickness of the belt to be formed thereon and a different cross-sectional shape below the parallel side wall portion which is the same cross-sectional shape as that of the belt desired to be produced, a thin flexible endless band having a width for running nicely between the parallel side walls of the pulleys, means for rotating at least one of the shafts and means for heating a belt being manufactured while it is run on the pulleys in the groove and beneath the thin flexible band.

6. The apparatus of claim 5 further characterized in that the shafts overhang the frame and the pulleys are mounted on the said overhanging shafts for easy mounting of the belts being manufactured and the endless band thereon.

'7. The apparatus of claim 5 further characterized in that the opposite ends of the shafts overhang the frame at each side and each shaft has a multiple groove pulley at each end thereof for manufacture of a plurality of belts of identical size simultaneously thereon.

8. The apparatus of claim 5 further characterized in that a stop is provided for limitin the relative movement of the shafts away from each other.

9. The apparatus of claim 5 further'characterized in that means is provided for preliminarily adjusting the parallel spacing of the shafts and in addition to the means for moving at least one of the shafts relative to the other while the shafts rotate.

10. The apparatus of claim 5 further characterized in that at least one of the pulleys is provided with electrical means for heating it.

11. The apparatu of claim 5 further characterized in that at least one of the pulleys is provided with electrical means for heating it and with thermostatic means for controlling the heat output of said electrical means for heating.

12. The apparatus of claim 5 further characterized in that it includes high-frequency electrical means for heating the belt being manufactured as it passes between the pulleys.

HENRY G. LYKKEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,969,067 Freeman Aug. 7, 1934 2,179,444 Bierer Nov. 7, 1939 2,195,125 Smith et al Mar. 26, 1940 2,418,976 Marcy Apr. 15, 1947 

